Kazakhstan says its athletes recorded five positives in retests of doping samples from the 2008 and 2012 Olympics.
Kazakhstan’s national Olympic committee says five “A” samples tested positive and that it has sent representatives to Switzerland to attend analysis of the “B” samples.
The athletes were not named and it was not immediately clear in which events they competed.
The Central Asian nation has faced repeated doping scandals in recent years, particularly in weightlifting and cycling.
The IOC is retesting samples from the Beijing and London Olympics to catch cheats who might be competing in Rio de Janeiro.
So far, 55 positives have been recorded 32 from Beijing and 23 from London.
Separately, the Russian Olympic Committee says two of its athletes’ “B” samples came back negative.
They are race walker Denis Nizhegorodov and rower Alexander Kornilov.